The field of art to which this invention pertains is the hydrodesulfurization of a high boiling range hydrocarbonaceous feedstock such as vacuum gas oil and the hydrocracking of another hydrocarbonaceous feedstock comprising light cycle oil. Petroleum refiners often produce desirable products such as turbine fuel, diesel fuel and other products known as middle distillates as well as lower boiling hydrocarbonaceous liquids such as naphtha and gasoline by hydrocracking a hydrocarbon feedstock derived from crude oil, for example. Feedstocks most often subjected to hydrocracking are gas oils and heavy gas oil recovered from crude oil by distillation. A typical gas oil comprises a substantial portion of hydrocarbon components boiling above about 371° C. (700° F.), usually at least about 50 percent by weight boiling above 371° C. (700° F.). A typical vacuum gas oil normally has a boiling point range between about 315° C. (600° F.) and about 565° C. (1050° F.). A light cycle oil (LCO) is produced during the fluid catalytic cracking (FCC) of gas oil feedstocks to primarily produce gasoline boiling range hydrocarbons. Light cycle oil is an undesirable refractory by-product of the FCC process and therefore is a low value product. Previously, LCO was blended into the diesel pool or used as cutter stock for heavy fuel oil. These traditional outlets are being diminished or eliminated because of the demands of the marketplace. LCO generally boils in the range of about 149° C. (300° F.) to about 371° C. (700° F.).
Although a wide variety of process flow schemes, operating conditions and catalysts have been used in commercial hydrodesulfurization and hydrocracking activities, there is always a demand for new methods which provide more useful products from distressed feedstocks and to provide improved product characteristics. The present invention is able to economically hydrocrack a first feedstock containing LCO in an integrated process while simultaneously desulfurizing a second feedstock containing high boiling range hydrocarbons. The higher boiling components of the second feedstock with a reduced concentration of sulfur compounds are an ideal feedstock for a fluid catalytic cracking unit (FCC).